arXiv subjects

Jih-Chiang Tsai

Publications and source records attributed to Jih-Chiang Tsai.

5 recordsLinked to original sources

arXiv2026

Quaking in Soft Granular Particles with Speed-dependent Friction: Role of Critical Volume Fraction and Inertia

Our previous numerical simulation [C.-E. Tsai et al., Physical Review Research \textbf{6}, 023065 (2024)] has shown that, for soft granular particles under quasistatic shearing, incorporating a speed-dependent friction is essential to reproduce the rate-dependent stick-slip fluctuations that have been found in the laboratory experiment [J.-C. Tsai et al., Physical Review Letters \textbf{126}, 128001 (2021)]. As a continuation, here we employ the simulation in a wide range of driving speeds to examine the role of grain inertia in the quaking dynamics. With our Stribeck-Hertz model, we find that having the volume fraction exceeding a critical value $ϕ_{\text{c}}$ is a necessary condition for the quaking to occur, and that the value of $ϕ_{\text{c}}$ is determined by material parameters only, independent of the driving rate. The effect of grain inertia generally suppresses the occurrence of quaking, and we conclude by presenting the state diagrams which exhibit a progressive narrowing of the quaking regime as the driving speed increases and the disappearance of quaking at an extremely high shear rate.

cond-mat.soft↗

arXiv2025

Internal motion of soft granular particles under circular shearing: Rate-dependent quaking and its spatial structure

Tightly packed granular particles under shear often exhibit intriguing intermittencies, specifically, sudden stress drops that we refer to as quaking. To probe the nature of this phenomenon, we prototype a circular shear cell that is capable of imposing a uniform and unlimited shear strain under quasi-static cyclic driving. Spherical PDMS(polydimethylsiloxane) particles, immersed in fluid, are driven in a fixed total volume at a wide range of shear rates, with particle trajectories captured in 3D space via refraction-index-matched fluorescent tomography. Statistics on the magnitude of fluctuating displacements of individual particles shows distinct dependence on the shear rate. Particle motions are smooth at high shear rates. At intermediate shear rates, quaking emerges with clusters of particles exhibiting relatively large displacements. At low shear rates, a cluster can span the entire system. and the cluster exhibits substructures in view of localized particle movements. Overall, we have confirmed that the quaking phenomena in the current setup are consistent with our previous work [Phys. Rev. Lett.,126, 128001 (2021)], and that the dimensionless shear rate that we have proposed [Phys. Rev. Research 6, 023065 (2024)] is indeed a good parameter for unifying the transitions observed in different experimental geometries.

cond-mat.soft↗

arXiv2023

Dynamical force measurements for contacting soft surfaces upon steady sliding: Fixed-depth tribology

The tribology between surfaces can have a profound impact on the response of a mechanical system, such as how granular particles are driven to flow. In this work, we perform experiments that time-resolve the tangential and normal components of the force between two semi-cylindrical PDMS (polydimethylsiloxane) samples immersed in fluid, as they slide against each other in a range of controlled speeds. The time-averaged friction force shows a non-monotonic dependence on the sliding speed over four decades, which is consistent to the paradigmatic Stribeck diagram and three dynamical regimes associated with it. Our specially designed fixed-depth setup allows us to study the fluctuation of force that exhibits strong stick-slip patterns in one of the regimes. Data from repetitive experiments reveal that both the "onset speed" for the stick-slip patterns and its spatial location along the sample change gradually during the course of our experiments, indicating changes on the sample surfaces. In addition, we conduct counterpart experiments by using spherical samples rubbing against each other, to make a direct connection of the inter-particle tribology to the granular flow reported in our previous work [Phys. Rev. Lett. 126,128001 (2021)].

cond-mat.soft↗

arXiv2021

Phase Diagram and Snap-Off Transition for a Twisted Party Balloon

All children enjoy inflating balloons and twisting them into different shapes and animals. Snapping the balloon into two separate compartments is a necessary step that bears resemblance to the pinch-off phenomenon for water droplet detached from the faucet. In addition to testing whether balloons exhibit the properties of self-similarity and memory effect that are often associated with the latter event, we determine their phase diagram by experiments. It turns out that a common party balloon does not just snap. They in fact can assume five more shapes, i.e., straight, necking, wrinkled, helix, and supercoil, depending on the twist angle and ratio of its length and diameter. Moreover, history also matters due to their prominent hysteresis. One may shift the phase boundary or/and reshuffle the phases by untwisting or lengthening the balloon at different twist angle and initial length. Heuristic models are provided to obtain analytic expressions for the phase boundaries.

cond-mat.soft↗

arXiv2020

Aging-Induced Dynamics for Statically Indeterminate System

Statically indeterminate systems are experimentally demonstrated to be in fact dynamical at the microscopic scale. Take the classic ladder-wall problem, for instance. Depending on the Young's modulus of the wall, it may take up to twenty minutes before its weight saturates. This finding is shown to be shared by other statically indeterminate systems, such as a granule silo and a beam with three support points. We believe that the aging effect is responsible for this surprising phenomenon because it can be correlated with the evolution of microscopic contact area with the wall and floor. Finally, a heuristic and simple method is introduced that can uniquely determine and analytically solve the saturated weight without invoking detailed material properties.

cond-mat.soft↗